The present invention relates to medical drainage pumps and, more particularly, to medical drainage pumps having means for controlled drainage of body fluids under suction and also having means for periodically infusing an irrigating fluid for clearing blood, mucous, or other material from the system. In addition, the medical drainage pumps are useful for controlled infusion of medication into the system.
Medical drainage pumps are conventionally used during surgery or medical treatment to drain body fluids from body cavities. One such medical drainage pump is disclosed in my prior U.S. Pat. No. 3,429,313, in which a double-action vacuum/pressure pump produces both a vacuum for drainage and an air pressure for controlling irrigation using an intermediate fixed- volume irrigation cylinder. Transfer between drainage and irrigation is controlled by a plurality of cams on a rotating wheel. The cams contact a lever, thereby operating a spool valve for cutting off drainage and directing air pressure to the irrigation cylinder. The irrigation cylinder then executes a single cycle for infusing a predetermined quantity of irrigation fluid into the body cavity.
The control system in the above patent requires numerous mechanical components thereby adding to the cost. The cam-type control lacks flexible control of drainage and irrigation.